If it’s a perennial problem that you keep hearing about, maybe there’s something to it. I will note, I did not once ask “why servers”. I’m fine with servers and I get servers. The issue I see is that while most nerdy tech type folks can easily wrap their heads around the concept, most lay people cannot. That’s not to say that picking a server of your liking should go away, but for the onboarding process for the masses, which I would think most proponents of the fediverse would want to include, the process needs to be a lot more seamless. Automated stuff in the background that keeps the decentralization, but doesn’t bother the user with the need to worry about it. It’s simply improving the user experience. I realize it’s work, but I think it’s work worth doing.
Being generous, let’s say 75% of reddit is bots. Then let’s say 10% of the actual people decide to move to Lemmy. That’s still 30 million people. The infrastructure is not ready for it. I’ve seen it happen in some bursts of interest, people swamp an instance, the instance doesn’t work because too much traffic, and people give up on the fediverse entirely because it didn’t work for them. If you want the fediverse to grow, you need to plan for growth, not just figure out a plan on the fly.